Embodiments of the present invention generally relate to a system and method for aerating a liquid, and more particularly to a system and method for aerating water within a pond and allowing undesirable gases to escape the water when the pond is iced over.
Fish ponds for personal enjoyment, as well as aquaculture, are found on various premises, including homes and businesses. Typically, expensive fish are kept in these ponds. As such, great care is taken to provide a suitable, safe environment for the fish. In order to maintain a suitable, safe environment for the fish, adequate levels of dissolved oxygen need to be maintained within the pond. At the same time, the presence of harmful gases, such as carbon dioxide or ammonia, need to be minimized.
Harmful gases may be introduced into the water through the decomposition of leaves and other organic matter, and fish waste. When the pond is iced over, these gases may build up to toxic concentrations, thereby endangering the fish.
Various systems and methods exist for allowing these harmful gases to escape and oxygen to enter the water. The most common method is to provide an opening in the ice through which gases may escape.
Conventional pond bubblers/aerators pump air into the pond. The air then bubbles to the surface. Gas exchange occurs as the bubbles break the water surface. Ice formation at the surface is typically hindered due to the turbulence caused by the bubbles. This method of aerating water, however, provides gas exchange that depends on the size of the bubbles and the amount of time the bubbles are in contact with the water. Additionally, any aeration that occurs is often localized, and icing may still occur at cold temperatures.
Heaters are commonly used to maintain openings in the ice, or in some cases, keep the pond free of ice. Heaters typically range in power from 100 watts up to 1500 watts, and therefore, may be expensive to operate. Additionally, heaters are often thermostatically controlled with a large hysteresis, so the water temperature in the pond may vary dramatically. Although heaters maintain a hole in the ice, aeration with heaters is achieved only at the passive interface between the water and the air. Also, water heaters may be domed over by snow and ice, thus sealing off the open water surface from the atmosphere.
Some systems use pumps that move relatively warmer water from the bottom of the pond to the surface where it is exposed to the atmosphere. The ground temperature is typically above freezing except during very cold freezes. The heat within the ground is transmitted to the water at the bottom of the pond. Thus, the water temperature at the bottom of the pond is typically several degrees warmer than at the top of the pond. Pumping the warmer water to the surface creates a localized area of warmer water that does not freeze. However, moving the water to the surface also exposes that water to the colder atmosphere. As such, the water may be supercooled, which may be very harmful to the fish.
Thus, a need exists for a more efficient system and method of aerating liquid within a water retention structure, such as a pond. Additionally, a need exists for a cost-effective system and method of aerating liquid that is not susceptible to being domed over by ice or snow. Further, a need exists for a system and method of liquid aeration that maintains liquid within the water retention structure at a safe temperature.